The glossily photographedfamily drama People Like Us is not without appeal, but it has a major construction flaw. It’s dramatic arc is predicated on the problem of accidental incestuous attraction. Egads. You know nothing will actually happen because this is a Disney movie, not a dreamy art film (like say Rebecca Miller’s The Ballad of Jack and Rose) but the whole movie marches toward the horrible moment when one of two newly acquainted half siblings, the more sympathetic one, will make a pass at the other and be rebuffed. It’s hideously compelling, like being in the room when one woman asks a woman who isn’t pregnant when she’s due, except that exchange is typically over in 30 spectacularly awful seconds and this one lasts two hours.

Sleazy and ambitious Sam Harper (Chris Pine), a professional barterer who trades surplus goods, deliberately arrives in Los Angeles too late for his father’s funeral. Sam’s mother (Michelle Pfeiffer) is chilly; after a childhood of being blown off by his father, Sam returned the favor when his father was dying of cancer. All he inherits from Jerry, an artistically successful (although less so financially) music producer, is his collection of vinyl. His dad’s lawyer (Philip Baker Hall, bestowing his usual gravitas on the proceedings) also gives him a shaving kit. It’s stuffed with cash, $150,000, and a letter inside directs Sam to deliver it to a Los Angeles address, which turns out to be that of the half sister Sam never knew he had.

The pronoun in the title should have been Him instead of Us, because single mom Frankie (Elizabeth Banks) looks just like Sam, blonde, blue-eyed, chiseled features, although Sam doesn’t catch on to the resemblance immediately. Puzzled as to the connection to his dad, he takes advantage of the Melrose Place-style open plan at her apartment complex to eavesdrop, then follows Frankie to a church basement where she waves Jerry’s obituary in the air and conveniently spills her story of childhood abandonment—and her connection to Sam—to a basement full of fellow Alcoholics Anonymous members. Sam is captivated by this new sister, a wheeler-dealer whose sharp tongue and tough exterior masks deep childhood pain and resentment; she’s just like him.

Without once identifying himself by last name or shared gene pool, Sam spends the next week or so making the single mom and her 11-year-old son Josh (Michael Hall D’Addario, in a performance right out of the young Tatum O’Neal’s playbook), a needy little punk, fall for him. He could just walk away with the money, which he needs since his dicey career has landed him in trouble with the Federal Trade Commission and his boss (Jon Favreau, who shows up for one scene). But his intentions to take it and run are thwarted. He’s drawn to his female mirror image, but not sexually. He wants a sister, and that—despite the secrets and lies—is sweet. Like Jerry Maguire, he’s a sleaze in search of a soul, and Frankie, even more neglected by and angry with their father, completes him. Pine is carving out a cocky, young Tom Cruise-style niche for himself; in his last movie, the miserable This Means War, he played an almost identical persona. He’s deft at portraying callow, even if his transformation into decency is harder to swallow.

Banks is really very good in the role of Frankie. She’s fierce and smart and intensely watchable. (As always. She lifted What to Expect When You’re Expecting out of the muck every time she appeared and gave the implausible Russell Crowe vehicle The Next Three Days its pulse.) Frankie is confused by the weird attentions of this guy who takes her out for tacos and asks probing questions about her life, but also flattered. She makes a living as a bartender at the Standard Hotel, but she’s having a hard time managing her mini-juvenile delinquent, who is always in trouble at school. Sam fosters her kid’s interest in music (he buys Josh London Calling the first time they meet) and stocks her refrigerator with groceries. Pine looks like a Ken doll whose forehead was elongated during a toddler tug-of-war, but from the eyes down, it’s all good, so who can blame lonely Frankie for being attracted to this sympathetic guy? He even pretends to be an alcoholic.

People Like Us has decent, even witty dialogue, a strong sense of place (Los Angeles, from Laurel Canyon to Neptune’s Net, feels like another character). A neat little ending stitches time and history together very neatly and poignantly, although the viewer is unlikely to let go of their negative feelings about dad Jerry Harper. If only director Alex Kurtzman, who shares a screenplay credit with his Star Trek co-writer, Roberto Orci, as well as Jody Lambert, hadn’t boxed himself into this corner. Essentially this is the same set up as the stereotypical romantic comedy where one party withholds a secret while the clueless one gives away his or her heart—only the looming revelation is not “I’m the hotel maid/your business rival/journalist who writing a hit piece on you” but “uh, I’m your brother so maybe let’s not kiss.” They’re relying on the misunderstanding for drama, but because they don’t want anything to seem too weird, they’ve given Sam a girlfriend (Olivia Wilde) who is across the country for most of the movie. She’s the audience’s reassurance that however weird it starts to seem with Sam and Frankie, this isn’t that kind film. But there’s plenty of potential here without this false drama. As You Can Count on Me demonstrated, the brother and sister dynamic is fertile territory. A sibling you didn’t even know you had? Even richer. Instead of dragging out the revelation, why not spend some time showing how Sam incorporates Frankie into the family? Pfeiffer is lovely in the scenes she does have, but she’s underused; why not throw her character into the room with the love-child? Sparks would fly but they wouldn’t be the kind that make you feel queasy.

Mary Pols has been reviewing film and occasionally books for TIME since 2009. She has degrees from Duke University, where she studied art history, and the University of California Berkeley’s School of Journalism. She is the author of a memoir about untraditional parenthood. It was made into a short-lived television comedy where everything turned out traditionally.

Accidentally on Purpose: The True Tale of a Happy Single Mother is available for nearly nothing at various online bookstores and from boxes in Pols' barn.